A wide variety of SONAR (sound navigation and ranging) units are used by anglers. These SONAR units may be commercialized as depth sounders or fish finders, and generally provide visual information on both the depth of the bottom (or other underwater structures) and the presence of fish below a boat hull, for instance, using a video display such as a liquid crystal display.
Existing depth sounders have grown quite sensitive, accurate and sophisticated over the last several years. In addition to showing a graphical representation of the bottom beneath a moving boat, modern depth sounders can display a three-dimensional image of the bottom structures (such as rock piles and the like) along with graphical representations specifically identifying sizes and numbers of fish.
While advantageous and able to graphically display very useful data, existing depth sounders are not without their limitations. In particular, when working fishing gear, it can be distracting for an angler to divert his attention from the fishing tackle, down-riggers, and the like, to view the graphical images being presented on the depth sounder. While the boat is moving, while down-riggers are being raised or lowered, while tackle is being added or removed, and while fish are being fought or landed, diversion of the angler's attention may lead to loss of boat control, loss of some fish, damage or loss of gear, or even injury to the angler. At a minimum, the angler will often find himself no longer fishing in productive waters. A wide variety of known depth sounder devices are known, including those described in U.S. Pat. Nos. 4,943,951; 5,537,380; and 6,198,692, which are incorporated by reference herein.
Certain attempts to remedy some of the aforementioned problems in conventional depth sounder systems and operation thereof have been made by including alarms that a user may present to provide a simple audio alert in the form of one or more “beeps” or “chirps” when certain parameters are met (e.g., bottom depth alarm, fish alarm or the like as programmed by a user). However, a user is clearly deprived of the variety of useful information provided by the sophisticated depth sounders or fish finders, since continuous feedback of underwater information is not possible without visual observation of the video display.
In light of the above, it would be desirable to provide improved depth sounders, for instance, advantageous to boaters, sport anglers or commercial fisherman. It would be particularly desirable for these improved devices to decrease the diversion of the user's attention from activities related to, for instance, working the boat gear or landing a fish, while enhancing the transfer of information from the depth sounder to the boater, angler or fisherman.